Navigation system and a method for guiding users, in particular drivers of vehicles

ABSTRACT

The present invention relates to a navigation system for guiding users, in particular drivers of vehicles, to a destination having a route computer ( 10 ) which determines a route, in particular a driving route, from a starting position and to a destination position and transmits it to a destination guidance unit ( 15 ) which in accordance with the route or driving route determined issues guidance directions to the user as a function of the user&#39;s current position at the time and having a user identification unit ( 17 ) which transmits a user identification signal designating the user is question to a destination input unit ( 11 ) which from current time and user position data and from user-specific information establishes a destination position for the determination of a route, in particular a driving route.

[0001] The invention relates to a navigation system and a method forguiding users, in particular drivers of vehicles, to a destination.

[0002] Navigation systems, that is systems which guide a user, inparticular a driver of a vehicle, from a starting point to adestination, are known. For this purpose, usually on the basis of streetmap information, a route from the starting point to the destination isdetermined in order to issue guidance directions visually and/oracoustically to the user according to the route determined and as afunction of the current position of the user in each case.

[0003] Usually, a user of a known navigation system must enter at leastthe destination position. In order to minimize the input effort by theuser, EP 805 951 discloses for a navigation system installed in avehicle the derivation of the destination position automatically alongprobability lines on the basis of a comparison of stored routeinformation from the past with current route information.

[0004] For this purpose in this known navigation system driving routesfrequently driven by the vehicle are stored as standard driving routesin a driving route memory. As soon as a new trip is started the startingposition and current time and driving route data are captured and storedin a working memory so that the start of the trip route currently beingdriven can be compared with the corresponding sections of the storedstandard driving routes. If the start of the trip route currently beingdriven matches a standard route the destination of this standard routeis selected as the end position of the trip route currently being drivenso that corresponding driving directions can be output to the driver ofthe vehicle.

[0005] In doing this it is possible in particular to take informationabout the current traffic situation into account in order to guide thedriver along the most favorable route to his destination.

[0006] Although in this known navigation system the input of the endposition by the driver is substantially simplified in the case of avehicle used by a number of people problems can arise in theidentification of the current destination position when, for example,two drivers frequently use driving routes to different destinationswhose initial paths coincide.

[0007] The underlying aim of the invention is to provide a navigationsystem and a method of guiding users, in particular drivers of vehicles,to a destination in which the automatic recognition of an end positionfor the calculation of a route, in particular a driving route, ensueswith increased reliability.

[0008] This task is solved by the navigation system according to Claim 1and by the method according to Claim 13.

[0009] Thus, according to the invention, in a navigation system a useridentification unit is provided which transmits a user identificationsignal designating the user in question to a destination input unitwhich from current time and user position data and from user-specificinformation establishes an end position for the determination of aroute, particularly a driving route. For this purpose a useridentification signal designating the user in question is detected inorder then from the current time and user position data and from theuser-specific information to determine an end position.

[0010] For this purpose it is useful if the destination input unit canbe connected to a memory device for user profiles describing userbehavior to date so that the appropriate user-specific information canbe accessed, the standard routes of a user taking account of assignedtime and frequency data being stored in the memory device as userprofiles.

[0011] Thus, according to the invention it is provided that for eachuser a user profile describing his behavior in the past is drawn up andstored.

[0012] In this way it is rendered possible that in a navigation systemused by a plurality of users, that is by way of example a navigationsystem installed in a vehicle used by a number of family members, theend position is determined only from the information specific to theuser in question, that is in particular with the aid of standard routes,which is assigned individually to the user in question.

[0013] In doing this it is particularly useful if each user profilecontains at least one standard route, time data being assigned to eachstandard route, and the destination of one of the standard routes isdetermined as the end position in the event that the time data for thestandard route match the current time data.

[0014] In order further to improve the reliability of the determinationof an end position it is particularly useful for an initial stretch of acurrent route actually taken by the user is recorded and compared withthe initial stages of stored standard routes and the destination of oneof the standard routes is established as the end position in the eventthat the start of one of the standard routes matches the initial patternof the current route actually taken by the user.

[0015] In order to simplify calculation of the route it is provided thatthe stored standard route assigned to the end position determined isidentified as the route to the destination.

[0016] In order to ensure that the initial stretch of the current routeactually taken by the user does not just match one of the standardroutes by chance, it is provided in a practical development of theinvention that a determined end position be displayed or announced tothe user for confirmation and only after confirmation be used as the endposition for the determination of the route.

[0017] In a particularly suitable development of the navigation systemaccording to the invention it is provided that the destination inputunit can be connected to a further memory device for user-specific endposition specifications so that the user-specific information inquestion can be accessed, route destinations with assigned timingsand/or starting positions being stored in each case as user-specific endposition specifications. Access by the destination input unit providedaccording to the invention to a further memory device is particularlyadvantageous when the navigation system is used with a vehicle which isused by numerous people, such as a vehicle in a company's motor vehiclefleet.

[0018] This development according to the invention allows the storage ina central memory for different drivers, for example, of the individualtrip destinations that the driver has to drive to and the takeover ofthe driving destinations allocated to the driver from the terminal unitin question of the navigation system installed in the vehicle on thebasis of the user identification. Thus, the route planning for aparticular member of staff or company driver can be done the day beforecompletely independently of the vehicle placed at the disposal of thedriver for this purpose.

[0019] Even if a vehicle is driven by only one person the invention isadvantageous since the destination of a route which is to be traveledfor the first time or only once can be conveniently entered from the PCat home or in the office. It is further conceivable that the input ofthe route destination and the selection of the route can be done, forexample, by a secretary or by a travel agency.

[0020] An advantageous refinement of the invention is characterized inthat the route computer and the destination guidance unit can beconnected to one another via an air interface, in particular via a radiointerface, and preferably via a mobile radio link in order to requestand transmit a route.

[0021] In a further development of the invention it is provided that theroute computer and the destination guidance unit are provided togetherin a user terminal unit and that the user terminal unit and thedestination input unit can be connected to one another via an airinterface, in particular via a radio interface, and preferably via amobile radio link in order to request and transmit an end position.

[0022] To identify the user in question of the navigation systemaccording to the invention it can be provided in the simplest case thatthe user identification unit possesses a plurality of switches of whicheach is assigned to one user. It is also possible for the useridentification unit to be linked to control elements in the vehiclewhich carry out certain user-specific adjustments, such as an automaticseat adjustment system or a rear mirror adjusting device.

[0023] It is, however, particularly advantageous when the useridentification unit comprises an identification data input circuit whichfor reading an identification data carrier can be connected to thelatter. By this means it is made possible to provide an electronic chipor a magnetic strip, for example, as the user identification carrier.This is particularly useful when, for example, a motor vehicle hiringcompany provides a user with a vehicle having a navigation system and atleast one driving destination of the user is to be preset.

[0024] In another refinement of the invention it is provided that theuser identification unit comprises an identification data input circuitwhich can be connected to a identification data output circuit of anidentification data carrier, the identification data input circuit ofthe user identification unit and the identification data output circuitof the identification data carrier being connectable to one another viaan air interface, in particular via a radio interface, and preferablyvia a radio interface having low power and range.

[0025] By this means it is made possible, for example, to use the keyidentification number stored in an electronic memory in a vehicle keywhich is transmitted to a security circuit via an air interface onstarting the vehicle for user identification also.

[0026] A useful development of the invention is characterized in that amobile telephone is provided as the identification data carrier, aninternal identification number of the mobile telephone or the mobileradio subscriber identification being used to generate a useridentification signal. The first identification number identifies themobile telephone and, via possession of the mobile telephone, the user.In the event, however, that a user possesses several instruments buthas, for example, only one mobile radio subscriber identification number(implemented, for example, by what are known as twin SIMs) even whenusing different terminal devices the user can be recognized/assigned asone and the same user of the navigation system.

[0027] In order to expand the possibilities of the navigation systemaccording to the invention it is provided that the user identificationunit and the destination input unit be connectable to one another via anair interface, in particular via a radio interface, and preferably via amobile radio link in order to transmit the user identification signaldesignating the user in question.

[0028] Particularly suitable guidance to a destination is achieved ifthe route is computed with current traffic situation information beingtaken into account, even when person-specific standard routes are usedsince in this way current traffic disturbances can be reliably bypassed.

[0029] Since commuters know their routes by heart and do not need routeguidance for their regular trips, it is not necessary to continuouslyoutput guidance information. However, they are interested to know ifthey will encounter any traffic jams on their routes and how to getaround them.

[0030] Therefore, according to a useful development of the presentinvention after determining a standard route stored as actual route ordriving route the user is prompted to select between a guiding mode inwhich guidance information is output, and a commuting mode in whichtraffic information is output but guidance information is output only incase that the standard route determined has been replaced by anotherroute in view of the actual traffic situation along the standard routedetermined.

[0031] In another refinement of the invention it is provided that afterselecting the commuting mode information identifying the selectedstandard route is transmitted to a traffic information system to monitorthe traffic situation along the selected standard route and to calculatean alternative route in accordance with the traffic situation ifnecessary to determine the fastest route to the destination, wherein theuser is preferably prompted to select one of the standard route and thealternative route.

[0032] Thus, standard routes are monitored upon user request based ontraffic information supplied by a traffic information system. This canbe done locally or preferably on a service provider side. Only in caseof predicted traffic congestion the service provider becomes active andsuggests an alternative route saving drive time.

[0033] The commuting mode is not only relevant for car navigation, butalso has potential in multimodal trips including public transportsystems and other means of transportation. A commuter using thosetransport systems is also interested if there are any delays of busses,trains and so forth. So the navigation system on the service providerside would not match positions against a database of all availablestreets to find out the route taken by the user, but instead would matchthose positions against possible used transport systems (e.g. which busline and what bus stops have been used). As in the car navigation systemthe user would only be informed if there are deviations from the typicalsetup. The system, in particular on the service provider side couldoffer an updated time table for the transportation system.

[0034] The invention is explained in more detail below with reference,by way of example, to the drawing. This shows:

[0035]FIG. 1 a simplified schematic block diagram of a navigation systemaccording to the invention;

[0036]FIG. 2 a simplified schematic block diagram of a navigation systemaccording to the invention in which a route computer of a serviceprovider is connected via an air interface to a destination guidanceunit which is accommodated in a user terminal device;

[0037]FIG. 3 a simplified block diagram of a further development of thenavigation system according to the invention in which the route computercommunicates via an air interface with a destination input device;

[0038]FIG. 4 a simplified diagram of a generic route comprising astarting point=ending point and n−1 intermediate destinations;

[0039]FIG. 5 a simplified diagram of two types of buffers for storingthe route segments; and

[0040]FIG. 6 a simplified diagram of a tolerance region around a storedroute segment in which a current route would be regarded as similar tostored route.

[0041] As FIG. 1 shows, a navigation system according to the inventionfor guidance to a destination, in particular for guiding drivers ofvehicles along a driving route, possesses a route computer 10 which isconnected on the input side to a destination input unit 11, a road mapmemory 12, a traffic information system 13 and a position identificationmodule, in particular a GPS (global positioning system) module 14. Thus,on the basis of a destination position entered via the destination inputunit 11 and a current starting position transmitted by the GPS module14, on the basis of road map information from the road map memory 12 andtaking account of the data describing the current traffic situationsupplied by the traffic information system 13 the route computer 10 cancalculate the fastest or shortest route which is transmitted to adestination guidance unit 15 connected to the route computer 10.

[0042] The destination guidance unit 15 is connected to an input-outputunit 16 in order to issue guidance directions to the user as a functionof the actual position at the time reported by the GPS module 14 inaccordance with the route transmitted by the route computer 10. In doingso the guidance directions can be output visually and/or acoustically.

[0043] The destination input unit 11 is connected on the input side to auser identification unit 17 and preferably also to the GPS module 14 inorder to receive a user identification signal designating the user inquestion and a signal identifying the current position.

[0044] The destination input unit 11 is further connected to a memorydevice 18 in which for each user a user profile describing the behaviorof the user to date is stored. In this case the user profile consists ofat least one standard route which is frequently traveled by the user inquestion. Time and frequency data are also assigned to the standardroute or routes. For example, for a user who drives every morningbetween 8.00 and 9.00 o'clock from his home to his place of work and inthe evenings between 17.00 and 18.00 back home or to his sports clubthree standard routes are stored, that is to say the route from home towork, the route from work to home and the route from work to sportsclub.

[0045] If it is now assumed that when the user leaves work at almostexactly 17.45 he is driving to the sports club, it can be recognizedwith near certainty on the basis of the current time and the known userbehavior whether the user who starts a trip from his place of workbetween 17.00 and 18.00 intends to travel home or to his sports club.Accordingly, the destination input unit 11 then transmits thedestination position, that is the position data for the user's home orfor the sports club, to the route computer 10.

[0046] If in the simplest case only the starting and end position of thestandard routes traveled by the user are stored together with the timeand frequency data the route computer 10 calculates the route afresh onthe basis of the road map information from the road map memory 12 andpossibly taking account of current traffic information from the trafficinformation system 13 in order then to transmit it to the destinationguidance unit 15 for the usual guidance to a destination.

[0047] It can, however, also be provided that the standard routes arestored with all driving directions in the memory 18 and possibly alsowith variants and/or detours. In this case the complete stored drivingroute data can be transferred to the route computer 10 which then eitherpasses on this driving route data directly to the destination guidanceunit 15 or compares it first with current traffic information so thatpossible traffic disturbances on the selected route can be taken intoaccount.

[0048] According to an advantageous refinement of the invention it isfurther possible that after a standard route has been established on thebasis of time and frequency data and the starting position the routeactually taken by the user is recorded so that the initial course of theactual route can be compared with the standard route determined in ordereither to confirm the latter or to determine a different standard routeor, in the event that none of the stored standard routes matches theinitial course of the route actually traveled, to call on the user toenter a destination position.

[0049] Via a data input port 19 the destination input unit 11 can beconnected to a further memory device for user-specific destinationposition specifications in which for a certain user route destinationspossibly together with associated starting positions are stored. Indoing this the data connection can be either direct or, in the eventthat this further memory device is arranged externally, be establishedvia an air interface, for example via a radio interface, and inparticular via a mobile radio link. At the same time user-specific datacan be input in any suitable manner.

[0050] As shown in FIG. 1 the user identification unit 17 possesses anidentification data input circuit 20 which is constructed for reading anidentification data carrier 21. In this case the identification datainput circuit 20 can be, for example, a magnetic-strip or memory-chipreading device when the identification data carrier 21 is an identitycard provided with a magnetic strip or a memory chip. However, theidentification data input circuit 20 can also be a receiving circuitwhich either automatically reads the security code information stored ina vehicle key or to which this information is transmitted by the vehiclecontrol device.

[0051]FIG. 2 shows a navigation system in which a mobile user terminaldevice 22, installed in a vehicle for example, comprises in addition tothe destination guidance unit 15, the GPS module 14 and the input-outputunit 16 only the user identification unit 17 and an interface unit 23.In this case the interface unit 23 can be a transmitter/receiver moduleof a mobile radio unit so that the user terminal device 22 cancommunicate via an air interface with a fixed station 24 of a serviceprovider. The fixed station 24 possesses a corresponding interface unit25 through which the route computer 10 and the destination input unit 11can exchange data with the user terminal device 22.

[0052] Furthermore, the road map memory 12 together with the trafficinformation system 13 and the first memory device 18 for storing theuser profiles are assigned to the fixed station 24.

[0053] Here the identification data carrier is a mobile telephone 21,for example, whose internal mobile equipment identity (IMEI) or themobile radio subscriber identification number is used for useridentification. To detect the subscriber identification number mobiletelephones have a corresponding reading device for the person-relatedSIM card or identification card. For practical reasons person-relatedidentification cards can also have smart media or cheque card format.

[0054] On start-up of the navigation system the equipment identificationnumber or the mobile radio subscriber identity serving for useridentification is transmitted via an air interface, for example aninfrared interface or a radio interface, and in particular a radiointerface having low transmitting power and range (LPRF [low-power RF]interface). For the identification data output circuit 26 the airinterface comprises a transmitter/receiver unit housed in the mobiletelephone 21′ together with a transmitter/receiver unit 27 of the useridentification unit 17 serving as the identification data input circuit.

[0055] The navigation system explained with reference to FIG. 2 can beused both for individual drivers using their own vehicle as well as forindividual drivers driving a vehicle from the motor vehicle fleet oftheir own company. Moreover, the navigation system according to theinvention, in which the destination input unit 11 is separate from themobile user terminal device 22, allows even more flexible use so thatguidance to a destination also becomes possible for passengers in ataxi.

[0056] For example, a user who has ordered a taxi in advance can notonly specify his travel destination when ordering in advance but alsohis user identification number for the navigation system so that thetravel destination of the user together with his identification numbercan be entered into the memory 18 via the data input port 19 and thedestination input unit 11 without it having to be established at thispoint which taxi should drive the user to his destination.

[0057] When the user now gets into a taxi which is equipped with acorresponding user terminal device 22 the user's mobile telephone 2reports to the user terminal device 22 via the air interface 26, 27 andtransmits the user identification number to the user identification unit17. The latter passes on the user identification number via the airinterface 23, 25 to the service provider 24. There the destination inputunit 11 reads out from the memory 18 the destination position assignedto the user and transmits it to the route computer 10. The routecomputer 10 now determines in the usual way the route to the desiredtravel destination of the passenger in the taxi and transmits this viathe air interface 23, 25 to the user terminal device 22 in the taxi inwhich the passenger in question is seated. The user terminal device 22then issues driving directions to the taxi driver in the usual way sothat the latter is guided on the optimum driving route in accordancewith the traffic situation at the time to the destination of hispassenger.

[0058] It is, furthermore, possible to use the navigation systemaccording to the invention also for passengers in a collective taxi whowish to go to different driving destinations. For this purpose thedesired destination for each passenger is determined in the fixedstation 24 of the service provider in the manner described above so thatthe route computer 10 can calculate the most favorable route for allpassengers to the various driving destinations.

[0059]FIG. 3 shows a further navigation system according to theinvention in which the route computer 10 and road map memory 12 areintegrated into the terminal device 22 while the destination input unit11 together with the memory device 18 for user profiles and the furthermemory device 28 are provided in a fixed station 29. In doing this, dataexchange between the user identification unit 17 and the destinationinput unit 11 and between the route computer 10 and the destinationinput unit 11 takes place via an air interface 23, 25″, while via asecond air interface 23, 25′ traffic information is transmitted from atraffic information system 13 to the user terminal device 22.

[0060] The mode of operation of the navigation system illustrated inFIG. 3 is the same as that described above regardless of how theindividual functional groups, that is in particular the route computer10, the destination input unit 11, the traffic information system 13 andthe destination guidance unit 15, are distributed over the individualmobile and fixed stations. Different distributions of the individualcomponents of the navigation system over various mobile or fixedstations have been described here by way of example. However, differentdistributions are also possible depending on the special requirementsimposed on the navigation system for the determination of user-specificdestination positions.

[0061] If, for example, destination specifications are to be stored forthe customers of a vehicle hire company, so that, for example, when ahired vehicle is picked up at the airport the customer can be guidedquickly to his hotel, it can be useful for the destination input unit 11together with the further memory unit 28 to be provided in a fixedposition in the headquarters of the vehicle hire company, while theroute computer 10 is arranged in a fixed position in the station 24 ofthe service provider. The individual stations can then exchange datawith one another via radio interfaces.

[0062] Another embodiment of the invention will now be explained withreference to the FIGS. 4 to 6. The local terminal, i. e. the mobile userterminal device 22 has a positioning subsystem (e.g. the GPS module 14)which periodically provides position information (e.g. once a second).During every trip all the position trajectories are saved in a protocolfile. Starting and end points for those trajectories are found if thevehicle stops at approximately the same position for a longer period oftime. In order to speed up the possibility of using the commuting modethe user could explicitly notify the system at the start and end point.The system locally checks all routes with the same start and end pointsfor their identity. If they are almost identical they are only storedonce. In addition the frequency of using the different routes is saved.

[0063] When the system is started it checks if there are one or morestandard routes starting at the current position which are usedfrequently. The system then prompts the user at the starting point ifthe commuting mode should be activated for a selected standard route.When the user accepts the commuting mode for the first time the completetrajectory of the standard route is transferred to a service providerwhere it is stored for future use. The service provider associates aroute ID with the trajectory and returns it to the mobile user terminaldevice 22. During subsequent activation of the commuting mode for thisroute only the route ID has to be transferred to the service provider.

[0064] If several destination points are stored which are reached fromthe same starting point usage of the calendar address entries could helpto disambiguate the route under consideration.

[0065] The system on the service provider side checks the trafficconditions for the activated route automatically in the background andonly notifies the driver if there is a traffic jam and a planned detourresults in saved drive time. The detour is already planned at theservice provider side and can be sent to the driver if she/he acceptsthe detour proposal. For a commuter the off board navigator only becomesactive in case the normal route contains obstacles and the user acceptsa planned detour.

[0066] In more detail, a commuter trip can normally be described as around trip with a starting point p₁, some intermediate destinations p₂ .. . p_(n) and returning to p₁. An intermediate destination differs fromother points on the route by a parking time exceeding a limit (say ofone hour e.g.). This generic route is depicted in FIG. 4.

[0067] Some special cases exist: If n=1 we have a round trip withoutlonger pauses (e.g. postal cars with fixed list of handover points). Ifn=2 we have the typical commuter setup, i.e. driving between home andwork back and forth.

[0068] Some of the route segments S_(i) between p_(i) and p_(i+1) mightbe identical nearly always, but some other segments can vary (e.g. dueto shopping). Therefore, only the learning of the different routesegments S_(i) (p_(i) to p_(i+1)) is considered without loss ofgenerality in order to simplify the algorithmic basis.

[0069] A route segment S_(i) is characterized by a sequence of N_(i)positions in time {x_(n)}, n=1, 2, . . . N_(i) with a starting points_(i)=x_(i) and an endpoint e_(i)=x_(Ni).

[0070] A starting point s_(i) is assigned if the parking time atposition s_(i) has exceeded a it threshold (e.g. one hour) and thesystem starts moving again or optionally if the system is turn on again(but the one hour park time has not yet expired). An endpoint is reachedif the system is parked at e_(i) for a period longer than the abovementioned threshold (i.e. again one hour e.g.) or as above if the systemis turned off. By definition, an endpoint e_(i) is also a starting points_(i+1) for the next route segment S_(i+1).

[0071] As illustrated in FIG. 5 route segments S_(i) can be stored in afirst (pruned) buffer 50 containing the position x_(n) trajectories of anumber R of route segments S_(i). A second buffer 51 contains astructure for start s_(i) and endpoints e_(i) for each route segmentS_(i) and a pointer pointing to the first buffer 50 containing thetrajectories.

[0072] In addition a third array buffer 52 for characterizing thestarting points s_(i) is favorable. This buffer 52 comprises theposition of the starting points of the route segments S_(i), thecumulative daily presence time t_(i) at the starting point s_(i) and thedaily frequency f_(di) of using it as starting point of a trip.

[0073] For a new route segment S_(i) the system reserves a buffer offixed length which cannot be exceeded (or has to be reallocated). When astarting point si is found the buffer 50 is continuously filled withpositions x_(n) (e.g. update every second). If the position does notchange significantly between subsequent samples. i.e.

|x _(n+1) −x _(n)|<ε AND |x _(n+2) −x _(n)|<ε AND |x _(n+3) −x _(n)|<ε,. . .

[0074] then all samples after x_(n) are discarded and the time ismeasured until the system starts moving again. If this time interval islarger than the parking time threshold (e.g. 1 h) the endpoint e_(i) isfound, otherwise the buffer filling is continued.

[0075] The buffer 51 for start/endpoints contains the positions s_(i)and e_(i), the time duration needed to move from s_(i) to e_(i), calledΔt_(i), the frequency f_(i) of using route segment S_(i), the number ofpositions N_(i) in buffer i of the first buffer 50 and a pointer to it.In the case of the trip duration Δt_(i) the time for longer pauses whichare longer than a stop in front of a traffic light, but shorter than thethreshold which determines an end point (example: one hour) aresubtracted from the trip duration in order to reflect the effectivedrive time.

[0076] The time period Δt_(i) can be used by the service provider totune the predicted duration of a trip. The predicted time can becompared with the actual time for this segment and a user-specificscaling factor (due to different driving habits on the same streets) canbe applied.

[0077] The frequency of usage f_(i) of route segment S_(i) is adjustedevery time a route segment has ended:

f _(i)(n+1):=αf _(i)(n)+(1−α)r

[0078] wherein

[0079] f_(i)(1)=0.5, 0<α<1,

[0080] r=1 if route segment S_(i) has been taken or

[0081] r=0 if route segment S_(i) has not been taken

[0082] If a new route segment S_(i) is registered, the frequencyf_(i)(1) is initialized with 0.5. When it is not used any more the usagefrequency slowly decays to zero (i.e. the segment is not used). If onthe other hand the route segment S_(i) is used every day the frequencyis converging to 1 (i.e. the route segment S_(i) is used during alldays).

[0083] In order to ensure that the frequency values are not decaying tozero and thus cause numerical problems all values are normalized everytime when a trip has ended so that their sum is:${\sum\limits_{i = 1}^{R}\quad f_{\quad i}} = 1$

[0084] Only if a route segment S_(i) occurs frequently, i.e. f_(i)>δ,0.5<δ1, it is proposed as a regular commuting or standard route to theuser. The cumulative daily presence time t_(i) is adapted once a day bya first order recursive filter: t_(i)(n+1):=αt_(i)(n)+(1−α)t_(new),0<α<1 where t_(new) represents the current daily presence time.

[0085] Storing a complete route trajectory requires a large enoughbuffer or file storage means. E. g., a one hour trip with an (x, y)position every second requires with a four byte resolution per x/y value60×60×8=28800 bytes.

[0086] In order to mark certain route segments S_(i) as frequentlyoccurring the system has to be capable to classify routes as similar interms of route planning or to be distinct. Since a positioning systemhas inherent error sources a 100% match of the route segments S_(i) isalmost impossible, even if the driver used exactly the same routetrajectory. To make the situation even more complicated, start and endpoints s_(i), e_(i) might vary by purpose. e.g. due to the fact that thedriver always finds different parking spaces and/or lots. Therefore, theposition tolerance when comparing start/end point regions should behigher than in the middle of the route segment S_(i). The geometricconstraints for matching stored and current route segments S_(i) areillustrated in FIG. 6.

[0087] A new route segment S is labeled as similar to an already storedsegment S_(i) if

|s−s _(i) |<R AND |e−e _(i) |<R AND

[0088] more than 95% of all positions {x_(n)}, n=1, 2, . . . N_(i) ofthe new route segment S fall into a corridor of width R_(m) around thestored route segment S_(i).

[0089] As described above in detail, according to the present inventionthe navigation system stores routes and learns which routes are usedfrequently. It is possible to differentiate the routes in three groups,One kind of route is a round trip, the second is a trip between twofixed points e. g. between home and work and the last one are manydifferent routes and starting/end locations.

[0090] If the system detects that user takes a repeating route, i. e. astandard route, it automatically starts a request to him/her if he/shewants to activate the commuting mode.

[0091] In the commuting mode the user can approve or insert informationabout the name of the location. This interaction can be also triggeredby the system. If the user starts a trip from a stored starting pointthe system proposes to activate the commuting mode to go to a knowndestination.

[0092] For a round trip only the location of the starting point and acorresponding standard route have to be available. Than, the system canask to start a round trip, no more information is needed.

[0093] A trip between two fixed points, as the daily trip from home towork needs a name for both locations. The system can suggestcorresponding names like home and work. If one location is named theother location could be named automatically. If the trip starts at onelocation the user is offered to go to the other.

[0094] However, it is also possible, that the system detects thedestination position or location from the current way the user takes bycomparing the trajectory of the actual way with that of stored standardroutes.

[0095] Furthermore, an indicator to detect the home and work location isto evaluate the cumulative presence time t_(i) at a location s_(i) andespecially for home the frequency of occurrence f_(di) as a startingpoint.

[0096] With three locations or even more the system needs more help fromthe user. Default names for location can be home, work or numbered. Theuser has to enter the name of the location if the system could not makea suggestion or remember the default numbered name. If the trip startsthe system can offer the most probable destination but it has also tooffer the other possibilities. Likely it is more than one interactionfor the user with the system.

1. Navigation system for guiding users, in particular drivers ofvehicles, to a destination having a route computer (10) which determinesa route, in particular a driving route, from a starting position and toa destination position and transmits it to a destination guidance unit(15) which in accordance with the route or driving route determinedissues guidance directions to the user as a function of the user'scurrent position at the time and a user identification unit (17) whichtransmits a user identification signal designating the user in questionto a destination input unit (11) which from current time and userposition data and from user-specific information establishes adestination position for the determination of a route, in particular adriving route.
 2. Navigation system according to claim 1, characterizedin that the destination input unit (11) is connectable to a memorydevice (18) for user profiles describing the behavior of the user todate in order that the user-specific information in question can beaccessed.
 3. Navigation system according to claim 2, characterized inthat for the user profiles in each case the standard routes of a userare stored in the memory device with assigned time and frequency databeing taken into account.
 4. Navigation system according to claim 1, 2or 3, characterized in that the destination input unit (11) isconnectable to a further memory device (28) for user-specificdestination position specifications in order that the user-specificinformation in question can be accessed.
 5. Navigation system accordingto claim 4, characterized in that for user-specific destination positionspecifications in each case route destinations with associated timingsand/or starting positions are stored.
 6. Navigation system according toone of the preceding claims, characterized in that the route computer(10) and the destination guidance unit (15) are connectable to oneanother via an air interface (23, 25), in particular via a radiointerface, and preferably via a mobile radio link in order to requestand transmit a route.
 7. Navigation system according to one of claims 1to 5, characterized in that the route computer (10) and the destinationguidance unit (15) are provided together in a user terminal device (22)and that the user terminal device (22) and the destination input unit(11) are connectable to one another via an air interface (23, 25″), inparticular via a radio interface, and preferably via mobile radio linkin order to request and transmit a destination position.
 8. Navigationsystem according to one of the preceding claims, characterized in thatthe user identification unit (17) comprises an identification data inputcircuit (20) which for reading an identification data carrier (21) isconnectable to the latter.
 9. Navigation system according to one of thepreceding claims, characterized in that the user identification unit(17) comprises an identification data input circuit which is connectableto an identification data output circuit of an identification datacarrier.
 10. Navigation system according to claim 9, characterized inthat the identification data input circuit (27) of the useridentification unit (17) and the identification data output circuit (26)of the identification data carrier (21′) are connectable to one anothervia an air interface, in particular via a radio interface, andpreferably via a radio interface having low power and range. 11.Navigation system according to claim 9 or 10, characterized in that forthe identification data carrier a mobile telephone (21′) is provided,wherein the internal identification number of the mobile telephone (21′)or the mobile radio subscriber identification is used to generate a useridentification signal.
 12. Navigation system according to one of thepreceding claims, characterized in that the user identification unit(17) and the destination input unit (11) are connectable to one anothervia an air interface (23, 25″), in particular via a radio interface, andpreferably via a mobile radio link in order to transmit the useridentification signal designating the user in question.
 13. Method forguiding users, in particular drivers of vehicles, to a destinationhaving the following steps: capture of a user identification signaldesignating the user in question; determination of a destinationposition for the determination of a route, in particular a drivingroute, from current time and user position data and from user-specificinformation; and output of guidance directions to the user as a functionof his/her current position at the time in accordance with thedestination position determined.
 14. Method according to claim 13,characterized in that for each user a user profile describing his/herbehavior in the past is drawn up and stored.
 15. Method according toclaim 14, characterized in that each user profile contains at least onestandard route, wherein time data are assigned to each standard route,and that the destination of one of the standard routes is determined asthe destination position when the time data of the standard route matchthe current time data.
 16. Method according to claim 15, characterizedin that an initial course of a current route actually taken by the useris recorded and compared with the starts of stored standard routes andthat the destination of one of the standard routes is determined as thedestination position when the start of one of the standard routesmatches the initial course of the current route actually taken by theuser.
 17. Method according to claim 15 or 16, characterized in that thestored standard route assigned to the destination position determined isdetermined as the route for the destination guidance.
 18. Methodaccording to claims 13 to 17, characterized in that a determineddestination position is displayed or announced to the user forconfirmation and is used only after confirmation as the destinationposition for the determination of a route.
 19. Method according to claim13, characterized in that for the user-specific information at least oneroute destination which can be used as destination position is stored.20. Method according to one of claims 13 to 19, characterized in thatthe route is determined with current traffic situation information beingtaken into account.
 21. Method according to one of claims 13 to 19,characterized in that after determining a standard route stored asactual route or driving route the user is prompted to select between aguiding mode in which guidance information is output, and a commutingmode in which traffic information is output but guidance information isoutput only in case that the standard route determined has been replacedby another route in view of the actual traffic situation along thestandard route determined.
 22. Method according to claim 21,characterized in that after selecting the commuting mode informationidentifying the selected standard route is transmitted to a trafficinformation system to monitor the traffic situation along the selectedstandard route and to calculate an alternative route in accordance withthe traffic situation if necessary to determine the fastest route to thedestination.
 23. Method according to claim 22, characterized in that theuser is prompted to select one of the standard route and the alternativeroute.